Telephone signaling system.



E. A. MELLINGER.

TELEPHONE SIGNALING SYSTEM. APPLICATION FILED MAY 9. 1913.

1,140,329., Patented May18,1915.

mumelw lllfl zvzssza EDWARD A. MELLING'ER, CHICAGO, ILLINOIS.

TELEPHONE SIGNALING SYSTEM.

Specification of Letters Patent.

Patented May 18, 1915;.

. Application filed May 9, 1913. Serial No. 766,558.

- of (ook and State of Illinois, have invented a certain new and useful Improvement in Telephone Signaling Systems, of which the followingis a specification.

My invention relates to improvements in telephone systems, and more particularly to the provision of means'whereby a called subscriber may indicate to an operator the fact that a connection has been made with his line. which connection he desires to have released.

In automatic and semi-automatic telephone systems ditliculty is often experienced owing to the fact that when a connection is set up between a calling and a called subscriber. which connection can only be released by the calling subscriber, the called subscribers telephone is rendered inoperative for making a call as long as this connection is maintained. Thus a calling subscriber. can either negligently or maliciouslytie up another subscribers telephone by failing to hang up his receiver so as to release the connection which he has established with the other subscriber.

It is the object of my invention to provide means whereby the subscriber whose telephone is thus tied up can signal an attendant at the exchange, who can then release the connection from his him.

My invention is especially useful in connection with automatic or semi-automatic telephone systems, but in certain broader respects it is likewise of value in connection with manual systems.

For the purpose of more particularly describing my invention I have illustrated the same in connection with an automatic connector switch which is adapted to automatically connect with a subscribers line.

In the accompanying drawing I have represented diagrainniatically an automatic connector switch F connected with an auto matic subscribefis station A to which is allotted a line switclrC. This connector F is of the type disclosed in United States Letters latentNofSlhd'TG, granted March 13, 1906, to Keith, Erickson and Erickson, but slightly modified in order to adapt it For use in a two-wire system. Among othcindctails .it comprises a lino relay 60, vertical and rotary magnets 61 and 62, pri- 'entioi1, it is not thought necessary to vate magnet 103, release relay 63, release magnet (54, back-bridge relay 65, ringing relay (36 and a ringing out-ofi' relay 67.

The line switch C is of the general type disclosed in British patent to R. V. James No. 26,301 of 1906 and in the Western Electrician of Chicago, Illinois, of January 25, 1908, being, however, of"the particular form shown in British patent to T. G. Martin No. H19 of 1.910. It will, of course, be understood that a master switch is employed with each group of these line switches, but as this feature well known and is described in the patents referred to, and as the same forms no part of my present indescribe or illustrate the same.

The substation A is the well-known type, consisting of a receiver 2, transmitter 3, contact springs 9, 10 and 11, ringer 12, condenser 13 and an impulse transmitter or callingdevice represented by the impulse springs '-i and impulse wheel 5. Said calling device can, of course, be of any desired type. but I have represented diagrammatically one similar to that described-in British patent to S. G. S. Dicker No. 29,654, of 1910. i Connection is made with the connector switch F over the trunk conductors 99 and 99*, which connection can be established in any well-known manner, such as by autoiatic switches or by the aid of a manual operator's switchboard.

It will be seen that theconnector switch F is provided with the ringingrelay (36 by which ringing current is automatically applied to the called line. 'The ringing cut-ofi relay 07 is likewise provided, which operatcs in the well-known manner to prevent ringing current being applied to the'line after the called subscriber has answered. Associated with this relay 67 there is a pair of additional contact springs 151, one 0 which is connected to a relay 150 which is preferably made slow acting, the other terminal of which relay is connected to the battery B. This" relay cbntrois through the mediun oi: the springs 172 a local'circuit containing an audible signal 170 in the form of a bell and a visual signal 171 in the form of a lamp. The other contact spring 151 is connected to a spring 1K2 of the back-bridge relay ($5. This spring-152 is normally in engagement with the spring 199 which is connected to the wiper 106, which wiper,

When connection is made With a subscribers line, is connected to battery. This arrangement is such that the circuit of the relay 150 can only be completed after a connection has been made with a subscribers line and the relay 67 energized and the relay 65 deenergized.

In order to make my invention more clearly understood, I will now describe the operation of the connector F and the signaling device H when connection is established with :1 called line.

Aftera calling subscriber has extended his connection to the r/trunk conductors 99 and 99, which extend to the connector F, impulses are then transmitted over these trunk conductors in the well-known manner in order to first operate this connector in a verticaldirection, and then a second series of impulses are transmittcd over these conductors in order to rotate the switch on to the particular contact of the called subscribers line. In a two-wire system of the character I have illustrated the circuit for the line relay 60 of the connector switch is closed when connection is established with the trunk eonductors 99 and 99., The first series of impulses operates to decnergize this relay a varying number of times, depending upon the number of impulses, the de inergizing of this line relay closing the circuit of the vertical magnet 61, which operates to raise the shaft in the usual manner. After the last impulse of the series is delivered, the slow acting private relay 102, which is energized in series with-the vertical magnot, deiinergizes, thereby breaking the circuit of the private magnet 103 to allow the side switch to be released from the first to the second position, transferring battery connection from the vertical magnet 61 to the rotary magnet {32. The next series of impulses is then transmitted over the trunk conductors and these operate to deiinergize the line relay 60 in the same manner above described, but the deenergizing of he line relay now operates the rotary magnetto rotate the shaft wipers 104, 105 and 106 on to the contact of the called subscribers line. After the last impulse of this series has been delivered, the private magnet again deenergizes' and the side switch passes to the third position. Upon the side switch wiper 4:8 reaching the third position a circuit is closed'f-rom ground G through said side switch wiper' 48, private wiper 106' andthrough the hold-down coil 110 to the battery lead 100. The coil 110 energizes to attract-the armature 111 to force the springs'112 together. Thus the connection ,is completed through the side switch wipers 16 and 47 and through the springs 112 to the substation 11.: The connection with ground G also provides a guarding potential for the private contacts in the banksof the connectors through which the called subscriber may be reached to prevent any other subscriber obtaining connection with said line while it isbusy. Upon the side switch wiper 49 reaching third position battery current is supplied to the ringer relay 66, the circuit extending from ground Gr through the ringing interrupter 114:, through said relay (36, springs 113 and said side switch wiper The relay (36, upon energizing, disconnects the calling line from the called line and connects the ringing current generator 116 with the called line to signal the called subscriber. The circuit of the relay '66 is interrupted intermittently by the interrupter 111 so as not to ring the subscriber continuously.

Upon the subscriber at the substation A 49 to the battery lead- 100.

across the line and immediately, or as soon thereafter as the ringer relay (36 is dei nergized, the hack-bridge-relay G5 is energized to reverse battery to the calling subscribers line in the well-known manner. v same operation the ringing cut-oil relay 67 is energized overv acircuit extending from ground G" through the side switch wiper -18, conductor 202, spring 199 and its front contact and through the relay 67 to the battcry lead 100. The relay 67, upon energizing, breaks the circuit of the ringing relay at the springs 113 and closes alocking circuit-foritsclt', which circuit extends from ground G through the side switch wiper 48, springs 200 and relay 6.7 to the battery lead 100. p w. i

The connector switch isi'eleaswl over the calling end of the connection by opening the circuit which was closed over the trunk conductors 99 and 99 during conversation,

reaching its lowest position 'the circuit of the release magnetis opened at the spring 121.

Having now described the operation of the connector switch, I will describe the operation of the signaling device H by which an indication is given. when a" subscriber blocks or ties up some other subscribers By the line. Upon the called subscriber hanging up his receiver while the calling subscriber has his receiver oil the hook, the back-bridgc relay 65 dciinergizes, while the ringing cutoff relay 67 is still energized from ground G through the side switch wiper 4-S,springs 200 and through said relay to the battery lead 100. When the relay 65 de'nergizes, a

circuit is closed from ground G through i the side switch wiper 48, conductor 202,

through the contact of springs 199 and 152, conductor 203, through the contact of springs 151 and the Winding of the solenoid or plunger relay 150 to the battery lead It will thus be seen that I have provided.

a very simple and efiicient means whereby any called subscriber is enabled to signalan exchange attendant in case the calling subscriber either wantonly or negligently fails to release the connection within a reasonable time after the called subscriber has hung up his receiver. The exchange attendant will therefore ascertain which switch has made connection with the line which is thus blocked and release it,- thereby restoring said line to its normal operative condition. 7

While I have illustrated and described my invention in connection with a connector switch of a particular type, it will, of course, be understood thatvmy invention is not limited to such use, but is of much broader scope and is of value in connection with switchesof other types used in automatic or semi-automatic systems, and is also useful in connection with manual systems.

What I claim as my invention is 1. Ina telephone system, a subscribers line, automatically progressively movable means for establishing connection with said line, a signal, means for preventing the display of the signal when connection is first made with said line, and means for displaying said signal upon the subscriber replacing his receiver upon the switch hook after said connection has been established.

2. In a telephone system, a subscribers line, means for establishing a connection with said line, a signal, and slow acting means for operating said signal after the subscriber on said line replaces his receiver upon the switch hook after said connection line, a connector switch for establishing connection with said line, a relay in said connector, means for energizing said relay upon the response of the subscriber after connection has been established with the line, means for maintaining said relay in an energized position until said switch is released, a second relay, means for energizing said second relay upon the response of the subscriber, means for deenergizing said second relay when said subscriber replaces his receiver upon the hook, a signaling relay, and a circuit for said signaling relay controlled by said first two relays.

5. In a telephone system, a subscribers line, a connector switch for establishing connection with said line, a relay in said connector, means for energizing said relay upon the response of the subscriber after connection has been established with the line, means for maintaining saidr relay in an energized position until said switch is released,

a second relay, means for energizing said, second relay upon the response of the subscriber, means for deenergizing'said second relaywhen said subscriber replaces his receiver upon the hook, a signaling relay, and

a circuit for said signaling relay including normally open contacts of said first relay' and normally closed contacts of said second relay.

6., In a telephone system, a subscribers line, a connector switch for establishing connection with said line, a relay in said connector, means for energizing said relay upon the response of the subscriber after connec tion has been established With the line, means for maintaining said relay in an energized position until said switch is released, a

second relay, means for energizing said second relay upon the response of the subscriber, means for deenergizing said second relay when said subscriber replaces his receiver upon the hook, a signaling relay, and a circuit for said signaling relay adapted to be closed only after a connection has been established with said line and said first relay energized and said second relay deenergized'.

7. In a telephone system, a subscribers line, a connector switch for establishing connection with said line, a relay in said con; nector, means for energizing said relay upon the response of the subscriber after connection has been established with the line means for maintaining said relay in anenergized position until said switch is released, a second relay, means for energizing said second relay upon the response of the subscriber, means for deenergizing said second relay when said subscriber replaces his receiver upon the'hook, a slow acting signaling relay, and a circuit for said signaling relay controlled by said first two relays.

8. In a telephone system, a subscribers line; a connector switch for establishing connection with said line, a relay in said connector, means for ener izin said relay upon the response of the 'su seri er after connection has been established with the line, means for maintaining said relay in an en ergized position until said switch is released, a. second relay, means for energizing said second relay upon the response of the -sub-- .scriber, means for deenergizlng Silld' second relay when said subscriber replaces his receiver upon the hook, a slow actingsignaling relay, and a circuit for said signaling relay including normally open contacts of said first relay and normally closed contacts of saidsecond relay.

-9."In a telephone systenna subscribers line, a connector switch for establishing connection with said line, a relay in said connector, means for energizing said relay upon the response of the subscriber after connection I has been established with-the line, means for maintainingsaid relay in an energized position until said switch is released, a second relay, means for energizing said second'relay upon the response of the subscriber, means for dencrgizing said second relay when'said subscriber replaces his receiver upon the hook, a slow acting signaling relay, and -a circuit for said signaling relay adapted to be closedonly after a connection has been established with said line and said first relay energized and said second relay deenergized;

10. In a telephone system, a subsrribers line, means for establishing a connection with said line, a' pair of relays, means for energizing said relays upon the response of the subscriber after said connection has been established, means for deiinergizing one of sand relays when the subscriber replaces his receiver upon the book, a signal, and means controlled by said relays for operating said signal upon the subscriber replacing his receiver upon the hook.. I P 11, In a telephone system, a subscribefls line, an automatic connectorsWitch-for establishing connection with said line, means -for automatically supplying ringing current .to said line, a ringing cut-off relayadapted to be energized upon the response of the subscriber, means for locking said relay in energized position, a back; bridge relay.

adapted to be energized uponthe response of the subscriber, means for deenergizing said relay upon the subscriber replacing his receiver upon the hook, and a signaling relay lay in energized position, a back-bridge i'elay adapted to'be energized upon the re sponse of the subscriber, means for deenergizing said relay upon the subscriber rcplacing his receiver upon the hook, and a slow acting signaling relay including normally open contacts of said cut-off relay and normally closed contacts of said backbridge relay. f p

,Signed by me at London, England, this 22nd day of April, 1913.

IG DW All D A. M ELLIN iElt.

Witnesses: I

lrVAL'r-EI': .l l. Dniun MA N, Anni-arr Jonns. 

